Drupal and Paypal

The LM_Paypal module is not intended to be a full e-commerce solution, but it does provide some types of built-in PayPal payment notifications, and when payment is completed, LM_Paypal module receives and records the notification. It allows for very simple automated donations, subscriptions, and paid advertisements. You should evaluate this module to see if it meets your needs. There are some significant limitations, so be sure to read the issues queue to ensure that the module does what you want it to do.

Drupal and E-Junkie

E-Junkie is a lightweight online shopping cart and fulfillment system. This blurb, taken from their home page, describes the system.

For merchants selling downloads, we automate and secure the digital delivery of files and codes. If you are selling tangible goods, we automate the shipping calculation and inventory management. Our shopping cart has a built in sales tax, VAT, packaging and shipping cost calculator.

E-Junkie Drupal Integration

That sounds great, but how do I integrate E-Junkie with Drupal? At present, I have not found any third-party Drupal modules offering E-Junkie and Drupal integration.

There are integration examples and how-to posts floating around on the web, however:

Drupal and Ubercart

Ubercart is an extensible e-commerce system that provides native product and shopping cart management within Drupal. Configuration can be somewhat complicated, but it does offer a complete solution with numerous add-in modules. You should plan for significant configuration, customization, and theming effort if the standard appearance and features are not close to what you want.

Extension modules of varying quality are available, and these may help you implement the features you want–be sure to set up a test site and verify all functionality before "going live".